ABSTRACT
The benefits of lowering blood pressure (BP) are well established for the prevention of cardiovascular disease. While there are a number of pharmaceuticals available for lowering BP, there is considerable interest in using dietary modifications, lifestyle and behaviour changes as alternative strategies. Kukoamines, caffeic acid derivatives of polyamines present in solanaceous plants, have been reported to reduce BP. We investigated the effect of orally administered synthetic kukoamine A on BP in the Spontaneously Hypertensive Rat (SHR) laboratory animal model of hypertension. Prior to the hypertension study, we determined the safety of the synthetic kukoamine A in a single oral dose (5 or 10 mg kg-1 bodyweight) 14-day observational study in mice. No negative effects of the oral administration of kukoamine A were observed. We subsequently investigated the effect of daily oral doses of kukoamine A (0, 5, 10 mg kg-1 bodyweight) for 35 days using the SHR rat model of hypertension. The normotensive control Wistar Kyoto (WKY) strain was used to provide a baseline for normal BP in rats. We observed no effect of orally administered synthetic kukoamine A on arterial hypertension in this laboratory animal model of hypertension.
Subject(s)
Hypertension , Administration, Oral , Animals , Blood Pressure/physiology , Hypertension/drug therapy , Mice , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Spermine/analogs & derivativesABSTRACT
Flowers of the kiwifruit species Actinidia chinensis produce a mixture of sesquiterpenes derived from farnesyl diphosphate (FDP) and monoterpenes derived from geranyl diphosphate (GDP). The tertiary sesquiterpene alcohol (E)-nerolidol was the major emitted volatile detected by headspace analysis. Contrastingly, in solvent extracts of the flowers, unusually high amounts of (E,E)-farnesol were observed, as well as lesser amounts of (E)-nerolidol, various farnesol and farnesal isomers, and linalool. Using a genomics-based approach, a single gene (AcNES1) was identified in an A. chinensis expressed sequence tag library that had significant homology to known floral terpene synthase enzymes. In vitro characterization of recombinant AcNES1 revealed it was an enzyme that could catalyse the conversion of FDP and GDP to the respective (E)-nerolidol and linalool terpene alcohols. Enantiomeric analysis of both AcNES1 products in vitro and floral terpenes in planta showed that (S)-(E)-nerolidol was the predominant enantiomer. Real-time PCR analysis indicated peak expression of AcNES1 correlated with peak (E)-nerolidol, but not linalool accumulation in flowers. This result, together with subcellular protein localization to the cytoplasm, indicated that AcNES1 was acting as a (S)-(E)-nerolidol synthase in A. chinensis flowers. The synthesis of high (E,E)-farnesol levels appears to compete for the available pool of FDP utilized by AcNES1 for sesquiterpene biosynthesis and hence strongly influences the accumulation and emission of (E)-nerolidol in A. chinensis flowers.
Subject(s)
Actinidia/enzymology , Farnesol/metabolism , Flowers/enzymology , Plant Proteins/metabolism , Sesquiterpenes/metabolism , Actinidia/genetics , Actinidia/metabolism , Acyclic Monoterpenes , Alkyl and Aryl Transferases/genetics , Alkyl and Aryl Transferases/metabolism , Arabidopsis/genetics , Arabidopsis/metabolism , Base Sequence , Diphosphates/metabolism , Diterpenes/metabolism , Farnesol/analysis , Flowers/genetics , Flowers/metabolism , Gene Expression Regulation, Plant/genetics , Kinetics , Molecular Sequence Data , Monoterpenes/analysis , Monoterpenes/metabolism , Oils, Volatile/analysis , Oils, Volatile/metabolism , Phylogeny , Plant Leaves/enzymology , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Proteins/genetics , Polyisoprenyl Phosphates/metabolism , Recombinant Proteins , Sequence Analysis, DNA , Sesquiterpenes/analysis , Substrate Specificity , Nicotiana/genetics , Nicotiana/metabolismABSTRACT
A survey of linalool enantiomers in kiwifruit (Actinidia) flowers was conducted to determine their potential as sources of these valuable floral fragrances, and revealed a wide range of enantiomeric ratios. While flowers of A. polygama and A. chrysantha contained almost exclusively one enantiomer, most species contained significant amounts of both (R) and (S) isomers. In some species enantiomeric ratios of floral linalool differed between genotypes, full siblings, and in one case clones, and ratios changed from year to year as well as diurnally. Enantioselective biosynthesis of the linalool-derived furanoid and pyranoid linalool oxides was examined in flowers of an A. chrysantha and an A. polygama genotype. The flowers of both species produced almost exclusively (S)-linalool. A. chrysantha flowers incubated with rac-d5-linalool preferentially processed the (S)-isomer through to the linalool oxides. However, the A. polygama flowers were less discriminatory in their use of rac-d5-linalool and processed significant quantities of d5-(R)-linalool as well.
Subject(s)
Actinidia/chemistry , Flowers/chemistry , Monoterpenes/chemistry , Actinidia/genetics , Acyclic Monoterpenes , Genotype , Mass Spectrometry , Species Specificity , StereoisomerismABSTRACT
Lilac alcohol epoxide (2-(5-methyl-5-(oxiran-2-yl)-tetrahydrofuran-2-yl)propan-1-ol), a previously unreported monoterpene, was identified in the solvent extract of the flowers of seven Actinidia arguta genotypes. The diastereomeric lilac alcohol epoxides co-occurred with the lilac aldehydes and alcohols. Another compound, the lilac diol (2-(5-(1-hydroxyethyl)-5-methyl-tetrahydrofuran-2-yl)propan-1-ol) was synthesised as part of our efforts to identify the lilac alcohol epoxide.
